Chemical reaction blamed in Bethel fire

Denis J. O'Malley

Updated 11:44 pm, Friday, September 20, 2013

BETHEL -- A volatile substance in a Taylor Avenue chemical plant was blamed for a small fire Thursday night, but the facility's safety system and the town's Fire Department took the credit for preventing a much larger blaze.

Bethel Fire Chief Fred Ingram said crews received an automatic fire alarm from Vanderbilt Chemical at about 8:30 p.m. and within minutes employees of the plant called to confirm a fire in one of the plant's machines.

Carbon disulfide -- CS2 -- caught fire during a manufacturing process when it reached a temperature above its ignition point of 200 degrees, Ingram said. It was not yet clear how the substance reached such a temperature, he said.

A small fire broke out in the plant's scrubber system -- which cleans excess substances from other machinery at the plant, Ingram said -- and an automatic fire-suppression system activated.

That system works by releasing nitrogen in the area of the fire, which eliminates any oxygen.

"With no oxygen, (a fire) can no longer burn," Ingram explained.

The fire had been extinguished by the time fire crews arrived and it did not result in any structural damage, but a precarious situation remained as the carbon disulfide remained above its ignition temperature, Ingram said.

"The main problem was we had this highly flammable product contained in a reactor and it was above its auto ignition point, and the only reason it wasn't burning was it was contained with nitrogen," he said. An explosion might have occurred if oxygen was reintroduced, he said.

Ultimately, Ingram said, a controlled release of the substance was done safely.

"The air was tested and deemed satisfactory, and the chemicals in the tank were indeed stable," he said in an email.

The incident remains under investigation by Vanderbilt Chemical, the DEEP and the Bethel Fire Department, Ingram said.

The fire forced the Metropolitan Transportation Authority to suspend service on Metro-North's Danbury branch for several hours, as the facility abuts the tracks. Buses were temporarily substituted to connect the Danbury and South Norwalk stations.

A subsidiary of R.T. Vanderbilt Holding Co. Inc. in Norwalk, Vanderbilt Chemical's Bethel division supplies chemical products to industries including paint, plastic and petroleum, according to its website.